Wood, Landfill Gas Dominate R.I. Renewable Energy

By TIM FAULKNER/ecoRI News staff

Rhode Island still has plenty of high-carbon-emitting wood in its renewable-energy portfolio. According to a recent report, 34 percent of the "renewable" electricity in the state’s electric grid comes from power plants that burn wood, often from virgin forest. Virgin forest is synonymous with old-growth and hardwood forests, but in this case it means burning whole trees rather than wood residue and byproducts.

Critics of biomass power note studies showing that burning wood releases more carbon dioxide than coal, natural gas and oil. In addition to destroying natural habitat, the wood-fuel industry burns mature trees, one of the best sources for sequestering carbon dioxide.

The rapid switch from fossil fuels to woody biomass as a so-called “green” energy, especially in Europe, has been publicized in recent investigative reports. Excessive carbon dioxide emissions and the life-cycle impacts from energy-intensive processes such as the production of wood pellets are seen as more than offsetting any environmental benefits.

Proponents of biomass say properly managed forests create a net increase of trees. But a 2015 report by the National Resources Defense Council concludes that it take decades for new trees to recapture the carbon dioxide lost from burning mature trees for biomass energy.

In Rhode Island, the General Assembly passed legislation in 2016 extending the Renewable Energy Standard (RES) until 2035. In order to meet its annual benchmark, National Grid buys the electricity from qualified power generators in Rhode Island, across New England and in New York. The electricity is assigned to Rhode Island through the purchase of renewable-energy credits (RECs), which are sold by generators of wind, solar, woody biomass, hydroelectric power and landfill gas.

The RES extension, however, didn't include any provisions limiting National Grid from buying wood power from other states.

Currently, about 11 percent of electricity sent to local wall sockets is generated from renewable sources. Annual increases of about 1.5 percent are expected to grow renewable power to 38 percent by 2035.

State officials are counting on the RES extension to increase local wind and solar projects, as developers realize they have a buyer for their renewable electricity.

Heavily forested states such as New Hampshire and Maine have been promoting wood-energy development. In 2015, National Grid made up a shortfall in a renewable-electricity contract by buying power from woody biomass plants in New Hampshire.

Landfill gas drawn from the Central Landfill in Johnston and burned across the street at the Broadrock Renewables power plant is the largest renewable-power source delivering electricity to Rhode Island.

Landfill gas accounts for 45 percent of Rhode Island's renewable energy. Biomass is second at 34 percent, followed by hydropower at 8.6 percent, wind at 7.7 percent and solar at 3.7 percent.

According to the annual 2015 RES compliance report — the most recent from the state Public Utilities Commission — landfill gas is at its highest portion of the renewable portfolio since the RES began in 2007.

Biomass peaked in 2013, when it accounted for 50 percent of the RES. In 2014, wood power dropped to 30 percent. It jumped back to 34 percent in 2015, with the added purchase of woody biomass RECs from New Hampshire.

Other states have limited the use of woody biomass. Massachusetts commissioned a report in 2010 that discovered emission problems with wood energy. The state passed RES rules in 2012 that prohibit biomass power from facilities that burn virgin forest. The wood must also be sourced from byproducts from lumber mills and forestry residue. As a result, woody biomass accounted for only 8 percent of the Bay State’s RES portfolio in its most recent compliance report.

Massachusetts, however, passed a law in 2016 that adds woody-biomass power to the list of state-approved sources of renewable energy. While the rules are being written, critics worry that it will increase particulate pollution and carbon emissions. Critics say it would roll back the 2012 RES rules by making it difficult to track sustainable harvesting and burning practices of wood pellets and wood derived from other states.

The Rhode Island Office of Energy Resources (OER) says its recent expansion of several renewable-energy incentives will lead to more Rhode Island-based wind and solar projects and eventually reduce the state’s dependence on woody biomass.

“We should see a change in that reflected in the reality of these programs,” OER commissioner Carol Grant said.

Other details of the latest RES report:

Most woody-biomass electricity delivered to Rhode Island comes from power plants in New Hampshire. A smaller amount comes from Maine.

43 percent of Rhode Island's RES power is generated in state.

All of the state's hydropower comes from outside Rhode Island. 

National Grid manages the RES program. The total cost for the electricity supplier to comply with the RES program dropped for the second year in a row, to $13.96 million. National Grid also expects the cost to decrease in 2016 and 2017.